Roshni Valmiki, 12, and her 10-year-old brother Avinash were attacked on Wednesday morning while defecating on a public street in Bhakhedi village in the Shivpuri district of Madhya Pradesh state in central India, said local police deputy superintendent Viren Singh.

After being beaten with sticks, the siblings were taken to the district hospital where doctors declared them both dead, Singh said. Defecating in that village is banned, he added. The two siblings were believed to be on their way to visit their grandfather.

Police have arrested two brothers over the attack. Singh said the incident is still under investigation.

The authorities have given the family 60,000 rupees ($845) in financial assistance for the funeral costs and other expenses. Under India's law, they will also receive 400,000 rupees ($5,600) in compensation.

Both children were Dalit, an ethnic group in India that makes up just over 16% of the population, according to the country's most-recent census. Dalits are among the most marginalized groups in India, a legacy of the now-outlawed caste system which stratified Indian society for generations. Seen as "unclean," they are considered untouchable by the higher castes.

Following the deaths, Mayawati -- the first female Dalit chief minister in India who goes by only one name-- condemned the violence and said Dalits have been victims of all kinds of malicious atrocities.

She called on the government to explain why proper, indoor toilets were often not available in villages where Dalits and other lower castes lived.

Earlier this month, international human rights activists slammed a decision by the Bill and Melinda Gates Foundation to hand India's controversial Prime Minister an award in recognition of his work to improve sanitation in the country. The foundation defended its decision, saying that Narendrara Modi's efforts had helped millions have access to safe sanitation.

Chief Minister Kamal Nath called the incident "heartbreaking."

"The incident concerning the killing of two innocent children in Bhavkhedi village in Shivpuri district is very heartbreaking," he said in a tweet Wednesday. "Instructions for strict action against the accused and providing all possible help and protection of the family have been issued."

It's not the first time there has been violence against Dalits in India.

Last year, two men died after right-wing Hindu nationalists allegedly threw rocks at Dalits who were commemorating the 200th anniversary of a battle significant to the Dalit community. The deaths prompted unrest and violent protests, which led to at least 10 deaths.

In November, a 13-year-old Dalit girl was beheaded in Salem district of the southern state of Tamil Nadu. Police charged the alleged killer under an act that criminalizes caste-based violence.

CNN